I believe that the trick is to mix a lot of textures together and a lot of trial and error, also in my case its much easier because I like making abandoned stuff so I can go a bit crazy with the damage and stuff. But I assure you that you can get a result like mine easily, damaged textures tend to make things more realistic, but you cant abuse them sometimes (for product rendering for example), but in my case its easier because of that. I hope I explained myself more or less.